New method to prepare polycrystalline meta-thioboric acid, (HBS(2))(3)

A new method to prepare polycrystalline meta-thioboric acid (c-HBS(2)) has been developed and reported. HBS(2) was obtained as a vapor condensate by reacting H(2)S with B(2)S(3) in the vapor phase, and the optimal conditions for this reaction are reported. The X-ray and spectroscopic characterization suggest that the structure of thioboric acid is monoclinic and made up of hexagonal rings formed by trimer units, (HBS(2))(3). The present preparation route is facile, faster than other wet routes of thiolysis, and the reaction requires much lower temperatures, thus avoiding contamination by reactor materials.